Transparent light emitting diodes

ABSTRACT

A transparent light emitting diode (LED) includes a plurality of III-nitride layers, including an active region that emits light, wherein all of the layers except for the active region are transparent for an emission wavelength of the light, such that the light is extracted effectively through all of the layers and in multiple directions through the layers. Moreover, the surface of one or more of the III-nitride layers may be roughened, textured, patterned or shaped to enhance light extraction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. § 120 of:

U.S. Utility patent application Ser. No. 13/622,884, filed on Sep. 19,2012, by Shuji Nakamura, Steven P. DenBaars, and Hirokuni Asamizu,entitled, “TRANSPARENT LIGHT EMITTING DIODES,” now U.S. Pat. No.8,835,959, issued Sep. 16, 2014, which application is a continuationunder 35 U.S.C. § 120 of:

U.S. Utility patent application Ser. No. 11/954,154, filed on Dec. 11,2007, by Shuji Nakamura, Steven P. DenBaars, and Hirokuni Asamizu,entitled, “TRANSPARENT LIGHT EMITTING DIODES,” now U.S. Pat. No.8,294,166, issued Oct. 23, 2012, which application claims the benefitunder 35 U.S.C. Section 119(e) of:

U.S. Provisional Patent Application Ser. No. 60/869,447, filed on Dec.11, 2006, by Shuji Nakamura, Steven P. DenBaars, and Hirokuni Asamizu,entitled, “TRANSPARENT LEDS,”;

all of which applications are incorporated by reference herein.

This application is related to the following co-pending andcommonly-assigned applications:

U.S. Utility application Ser. No. 10/581,940, filed on Jun. 7, 2006, byTetsuo Fujii, Yan Gao, Evelyn. L. Hu, and Shuji Nakamura, entitled“HIGHLY EFFICIENT GALLIUM NITRIDE BASED LIGHT EMITTING DIODES VIASURFACE ROUGHENING,” now U.S. Pat. No. 7,704,763 issued Apr. 27, 2010,which application claims the benefit under 35 U.S.C Section 365(c) ofPCT Application Serial No. US2003/03921, filed on Dec. 9, 2003, byTetsuo Fujii, Yan Gao, Evelyn L. Hu, and Shuji Nakamura, entitled“HIGHLY EFFICIENT GALLIUM NITRIDE BASED LIGHT EMITTING DIODES VIASURFACE ROUGHENING,”;

U.S. Utility application Ser. No. 11/054,271, filed on Feb. 9, 2005, byRajat Sharma, P. Morgan Pattison, John F. Kaeding, and Shuji Nakamura,entitled “SEMICONDUCTOR LIGHT EMITTING DEVICE,” now U.S. Pat. No.8,227,820 issued Jul. 24, 2012;

U.S. Utility application Ser. No. 11/175,761, filed on Jul. 6, 2005, byAkihiko Murai, Lee McCarthy, Umesh K. Mishra and Steven P. DenBaars,entitled “METHOD FOR WAFER BONDING (Al, In, Ga)N and Zn(S, Se) FOROPTOELECTRONICS APPLICATIONS,” now U.S. Pat. No. 7,344,958 issued Mar.18, 2008, which application claims the benefit under 35 U.S.C Section119(e) of U.S. Provisional Application Ser. No. 60/585,673, filed Jul.6, 2004, by Akihiko Murai, Lee McCarthy, Umesh K. Mishra and Steven P.DenBaars, entitled “METHOD FOR WAFER BONDING (Al, In, Ga)N and Zn(S, Se)FOR OPTOELECTRONICS APPLICATIONS,”;

U.S. Utility application Ser. No. 11/697,457, filed Apr. 6, 2007, by,Benjamin A. Haskell, Melvin B. McLaurin, Steven P. DenBaars, James S.Speck, and Shuji Nakamura, entitled “GROWTH OF PLANAR REDUCEDDISLOCATION DENSITY M-PLANE GALLIUM NITRIDE BY HYDRIDE VAPOR PHASEEPITAXY,” now U.S. Pat. No. 7,956,360 issued Jun. 7, 2011, whichapplication is a continuation of U.S. Utility application Ser. No.11/140,893, filed May 31, 2005, by, Benjamin A. Haskell, Melvin B.McLaurin, Steven P. DenBaars, James S. Speck, and Shuji Nakamura,entitled “GROWTH OF PLANAR REDUCED DISLOCATION DENSITY M-PLANE GALLIUMNITRIDE BY HYDRIDE VAPOR PHASE EPITAXY,” now U.S. Pat. No. 7,208,393,issued Apr. 24, 2007, which application claims the benefit under 35U.S.C. Section 119(e) of U.S. Provisional Application Ser. No.60/576,685, filed Jun. 3, 2004, by Benjamin A. Haskell, Melvin B.McLaurin, Steven P. DenBaars, James S. Speck, and Shuji Nakamura,entitled “GROWTH OF PLANAR REDUCED DISLOCATION DENSITY M-PLANE GALLIUMNITRIDE BY HYDRIDE VAPOR PHASE EPITAXY,”;

U.S. Utility application Ser. No. 11/067,957, filed Feb. 28, 2005, byClaude C. A. Weisbuch, Aurelien J. F. David, James S. Speck and StevenP. DenBaars, entitled “HORIZONTAL EMITTING, VERTICAL EMITTING, BEAMSHAPED, DISTRIBUTED FEEDBACK (DFB) LASERS BY GROWTH OVER A PATTERNEDSUBSTRATE,” now U.S. Pat. No. 7,723,745 issued May 25, 2010;

U.S. Utility application Ser. No. 11/923,414, filed Oct. 24, 2007, byClaude C. A. Weisbuch, Aurelien J. F. David, James S. Speck and StevenP. DenBaars, entitled “SINGLE OR MULTI-COLOR HIGH EFFICIENCY LIGHTEMITTING DIODE (LED) BY GROWTH OVER A PATTERNED SUBSTRATE,” now U.S.Pat. No. 7,755,096 issued Jul. 13, 2010, which application is acontinuation of U.S. Pat. No. 7,291,864, issued Nov. 6, 2007, to ClaudeC. A. Weisbuch, Aurelien J. F. David, James S. Speck and Steven P.DenBaars, entitled “SINGLE OR MULTI-COLOR HIGH EFFICIENCY LIGHT EMITTINGDIODE (LED) BY GROWTH OVER A PATTERNED SUBSTRATE,” now U.S. Pat. No.7,291,864 issued Nov. 6, 2007;

U.S. Utility application Ser. No. 11/067,956, filed Feb. 28, 2005, byAurelien J. F. David, Claude C. A Weisbuch and Steven P. DenBaars,entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED) WITH OPTIMIZEDPHOTONIC CRYSTAL EXTRACTOR,” now U.S. Pat. No. 7,582,910 issued Sep. 1,2009;

U.S. Utility application Ser. No. 11/621,482, filed Jan. 9, 2007, byTroy J. Baker, Benjamin A. Haskell, Paul T. Fini, Steven P. DenBaars,James S. Speck, and Shuji Nakamura, entitled “TECHNIQUE FOR THE GROWTHOF PLANAR SEMI-POLAR GALLIUM NITRIDE,” now U.S. Pat. No. 7,704,331issued Apr. 27, 2010, which application is a continuation of U.S.Utility application Ser. No. 11/372,914, filed Mar. 10, 2006, by Troy J.Baker, Benjamin A. Haskell, Paul T. Fini, Steven P. DenBaars, James S.Speck, and Shuji Nakamura, entitled “TECHNIQUE FOR THE GROWTH OF PLANARSEMI-POLAR GALLIUM NITRIDE,” now U.S. Pat. No. 7,220,324, issued May 22,2007, which application claims the benefit under 35 U.S.C. Section119(e) of U.S. Provisional Application Ser. No. 60/660,283, filed Mar.10, 2005, by Troy J. Baker, Benjamin A. Haskell, Paul T. Fini, Steven P.DenBaars, James S. Speck, and Shuji Nakamura, entitled “TECHNIQUE FORTHE GROWTH OF PLANAR SEMI-POLAR GALLIUM NITRIDE,”;

U.S. Utility application Ser. No. 11/403,624, filed Apr. 13, 2006, byJames S. Speck, Troy J. Baker and Benjamin A. Haskell, entitled “WAFERSEPARATION TECHNIQUE FOR THE FABRICATION OF FREE-STANDING (AL, IN, GA)NWAFERS,” which application claims the benefit under 35 U.S.C Section119(e) of U.S. Provisional Application Ser. No. 60/670,810, filed Apr.13, 2005, by James S. Speck, Troy J. Baker and Benjamin A. Haskell,entitled “WAFER SEPARATION TECHNIQUE FOR THE FABRICATION OFFREE-STANDING (AL, IN, GA)N WAFERS,”;

U.S. Utility application Ser. No. 11/403,288, filed Apr. 13, 2006, byJames S. Speck, Benjamin A. Haskell, P. Morgan Pattison and Troy J.Baker, entitled “ETCHING TECHNIQUE FOR THE FABRICATION OF THIN (AL, IN,GA)N LAYERS,” now U.S. Pat. No. 7,795,146 issued Sep. 14, 2010, whichapplication claims the benefit under 35 U.S.C Section 119(e) of U.S.Provisional Application Ser. No. 60/670,790, filed Apr. 13, 2005, byJames S. Speck, Benjamin A. Haskell, P. Morgan Pattison and Troy J.Baker, entitled “ETCHING TECHNIQUE FOR THE FABRICATION OF THIN (AL, IN,GA)N LAYERS,”;

U.S. Utility application Ser. No. 11/454,691, filed on Jun. 16, 2006, byAkihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy,Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al,Ga, In)N AND ZnO DIRECT WAFER BONDING STRUCTURE FOR OPTOELECTRONICAPPLICATIONS AND ITS FABRICATION METHOD,” now U.S. Pat. No. 7,719,020issued May 18, 2010, which application claims the benefit under 35 U.S.CSection 119(e) of U.S. Provisional Application Ser. No. 60/691,710,filed on Jun. 17, 2005, by Akihiko Murai, Christina Ye Chen, Lee S.McCarthy, Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra,entitled “(Al, Ga, In)N AND ZnO DIRECT WAFER BONDING STRUCTURE FOROPTOELECTRONIC APPLICATIONS, AND ITS FABRICATION METHOD,” U.S.Provisional Application Ser. No. 60/732,319, filed on Nov. 1, 2005, byAkihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy,Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al,Ga, In)N AND ZnO DIRECT WAFER BONDED STRUCTURE FOR OPTOELECTRONICAPPLICATIONS, AND ITS FABRICATION METHOD,”, and U.S. ProvisionalApplication Ser. No. 60/764,881, filed on Feb. 3, 2006, by AkihikoMurai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy, Steven P.DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al, Ga, In)NAND ZnO DIRECT WAFER BONDED STRUCTURE FOR OPTOELECTRONIC APPLICATIONSAND ITS FABRICATION METHOD,”;

U.S. Utility application Ser. No. 11/444,084, filed May 31, 2006, byBilge M, Imer, James S. Speck, and Steven P. DenBaars, entitled “DEFECTREDUCTION OF NON-POLAR GALLIUM NITRIDE WITH SINGLE-STEP SIDEWALL LATERALEPITAXIAL OVERGROWTH,” now U.S. Pat. No. 7,361,576 issued Apr. 22, 2008,which claims the benefit under 35 U.S.C. 119(e) of U.S. ProvisionalApplication Ser. No. 60/685,952, filed on May 31, 2005, by Bilge M,Imer, James S. Speck, and Steven P. DenBaars, entitled “DEFECT REDUCTIONOF NON-POLAR GALLIUM NITRIDE WITH SINGLE-STEP SIDEWALL LATERAL EPITAXIALOVERGROWTH,”;

U.S. Utility application Ser. No. 11/870,115, filed Oct. 10, 2007, byBilge M, Imer, James S. Speck, Steven P. DenBaars and Shuji Nakamura,entitled “GROWTH OF PLANAR NON-POLAR M-PLANE III-NITRIDE USINGMETALORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD),” now U.S. Pat. No.8,097,481 issued Jan. 17, 2012, which application is a continuation ofU.S. Utility application Ser. No. 11/444,946, filed May 31, 2006, byBilge M, Imer, James S. Speck, and Steven P. DenBaars, entitled “GROWTHOF PLANAR NON-POLAR {1-100} M-PLANE GALLIUM NITRIDE WITH METALORGANICCHEMICAL VAPOR DEPOSITION (MOCVD),” now U.S. Pat. No. 7,338,828 issuedMar. 4, 2008, which claims the benefit under 35 U.S.C. 119(e) of U.S.Provisional Application Ser. No. 60/685,908, filed on May 31, 2005, byBilge M, Imer, James S. Speck, and Steven P. DenBaars, entitled “GROWTHOF PLANAR NON-POLAR {1-100} M-PLANE GALLIUM NITRIDE WITH METALORGANICCHEMICAL VAPOR DEPOSITION (MOCVD),”;

U.S. Utility application Ser. No. 11/444,946, filed Jun. 1, 2006, byRobert M. Farrell, Troy J. Baker, Arpan Chakraborty, Benjamin A.Haskell, P. Morgan Pattison, Rajat Sharma, Umesh K. Mishra, Steven P.DenBaars, James S. Speck, and Shuji Nakamura, entitled “TECHNIQUE FORTHE GROWTH AND FABRICATION OF SEMIPOLAR (Ga, Al, In, B)N THIN FILMS,HETEROSTRUCTURES, AND DEVICES,” now U.S. Pat. No. 7,846,757 issued Dec.7, 2010, which claims the benefit under 35 U.S.C. 119(e) of U.S.Provisional Application Ser. No. 60/686,244, filed on Jun. 1, 2005, byRobert M. Farrell, Troy J. Baker, Arpan Chakraborty, Benjamin A.Haskell, P. Morgan Pattison, Rajat Sharma, Umesh K. Mishra, Steven P.DenBaars, James S. Speck, and Shuji Nakamura, entitled “TECHNIQUE FORTHE GROWTH AND FABRICATION OF SEMIPOLAR (Ga, Al, In, B)N THIN FILMS,HETEROSTRUCTURES, AND DEVICES,”;

U.S. Utility application Ser. No. 11/251,365 filed Oct. 14, 2005, byFrederic S. Diana, Aurelien J. F. David, Pierre M. Petroff, and ClaudeC. A. Weisbuch, entitled “PHOTONIC STRUCTURES FOR EFFICIENT LIGHTEXTRACTION AND CONVERSION IN MULTI-COLOR LIGHT EMITTING DEVICES,” nowU.S. Pat. No. 7,768,023 issued Aug. 3, 2010;

U.S. Utility application Ser. No. 11/633,148, filed Dec. 4, 2006, ClaudeC. A. Weisbuch and Shuji Nakamura, entitled “IMPROVED HORIZONTALEMITTING, VERTICAL EMITTING, BEAM SHAPED, DISTRIBUTED FEEDBACK (DFB)LASERS FABRICATED BY GROWTH OVER A PATTERNED SUBSTRATE WITH MULTIPLEOVERGROWTH,” now U.S. Pat. No. 7,768,024 issued Aug. 3, 2010, whichapplication claims the benefit under 35 U.S.C Section 119(e) of U.S.Provisional Application Ser. No. 60/741,935, filed Dec. 2, 2005, ClaudeC. A. Weisbuch and Shuji Nakamura, entitled “IMPROVED HORIZONTALEMITTING, VERTICAL EMITTING, BEAM SHAPED, DFB LASERS FABRICATED BYGROWTH OVER PATTERNED SUBSTRATE WITH MULTIPLE OVERGROWTH,”;

U.S. Utility application Ser. No. 11/517,797, filed Sep. 8, 2006, byMichael Iza, Troy J. Baker, Benjamin A. Haskell, Steven P. DenBaars, andShuji Nakamura, entitled “METHOD FOR ENHANCING GROWTH OF SEMIPOLAR (Al,In, Ga, B)N VIA METALORGANIC CHEMICAL VAPOR DEPOSITION,” now U.S. Pat.No. 7,575,947 issued Aug. 18, 2009, which claims the benefit under 35U.S.C. 119(e) of U.S. Provisional Application Ser. No. 60/715,491, filedon Sep. 9, 2005, by Michael Iza, Troy J. Baker, Benjamin A. Haskell,Steven P. DenBaars, and Shuji Nakamura, entitled “METHOD FOR ENHANCINGGROWTH OF SEMIPOLAR (Al, In, Ga, B)N VIA METALORGANIC CHEMICAL VAPORDEPOSITION,”;

U.S. Utility application Ser. No. 11/593,268, filed on Nov. 6, 2006, bySteven P. DenBaars, Shuji Nakamura, Hisashi Masui, Natalie N. Fellows,and Akihiko Murai, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHTEMITTING DIODE (LED),” now U.S. Pat. No. 7,994,527 issued Aug. 9, 2011,which application claims the benefit under 35 U.S.C Section 119(e) ofU.S. Provisional Application Ser. No. 60/734,040, filed on Nov. 4, 2005,by Steven P. DenBaars, Shuji Nakamura, Hisashi Masui, Natalie N.Fellows, and Akihiko Murai, entitled “HIGH LIGHT EXTRACTION EFFICIENCYLIGHT EMITTING DIODE (LED),”;

U.S. Utility application Ser. No. 11/608,439, filed on Dec. 8, 2006, bySteven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “HIGHEFFICIENCY LIGHT EMITTING DIODE (LED),” now U.S. Pat. No. 7,956,371issued Jun. 7, 2011, which application claims the benefit under 35 U.S.CSection 119(e) of U.S. Provisional Application Ser. No. 60/748,480,filed on Dec. 8, 2005, by Steven P. DenBaars, Shuji Nakamura and JamesS. Speck, entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED),”, andU.S. Provisional Application Ser. No. 60/764,975, filed on Feb. 3, 2006,by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “HIGHEFFICIENCY LIGHT EMITTING DIODE (LED),”;

U.S. Utility application Ser. No. 11/676,999, filed on Feb. 20, 2007, byHong Zhong, John F. Kaeding, Rajat Sharma, James S. Speck, Steven P.DenBaars and Shuji Nakamura, entitled “METHOD FOR GROWTH OF SEMIPOLAR(Al, In, Ga, B)N OPTOELECTRONIC DEVICES,” now U.S. Pat. No. 7,858,996issued Dec. 28, 2010, which application claims the benefit under 35U.S.C Section 119(e) of U.S. Provisional Application Ser. No.60/774,467, filed on Feb. 17, 2006, by Hong Zhong, John F. Kaeding,Rajat Sharma, James S. Speck, Steven P. DenBaars and Shuji Nakamura,entitled “METHOD FOR GROWTH OF SEMIPOLAR (Al, In, Ga, B)N OPTOELECTRONICDEVICES,”;

U.S. Utility patent application Ser. No. 11/840,057, filed on Aug. 16,2007, by Michael Iza, Hitoshi Sato, Steven P. DenBaars, and ShujiNakamura, entitled “METHOD FOR DEPOSITION OF MAGNESIUM DOPED (Al, In,Ga, B)N LAYERS,” now U.S. Pat. No. 7,755,172 issued Jul. 13, 2010, whichclaims the benefit under 35 U.S.C. 119(e) of U.S. Provisional PatentApplication Ser. No. 60/822,600, filed on Aug. 16, 2006, by Michael Iza,Hitoshi Sato, Steven P. DenBaars, and Shuji Nakamura, entitled “METHODFOR DEPOSITION OF MAGNESIUM DOPED (Al, In, Ga, B)N LAYERS,”;

U.S. Utility patent application Ser. No. 11/940,848, filed on Nov. 15,2007, by Aurelien J. F. David, Claude C. A. Weisbuch and Steven P.DenBaars entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE(LED) THROUGH MULTIPLE EXTRACTORS,” which application claims the benefitunder 35 U.S.C Section 119(e) of U.S. Provisional Patent ApplicationSer. No. 60/866,014, filed on Nov. 15, 2006, by Aurelien J. F. David,Claude C. A. Weisbuch and Steven P. DenBaars entitled “HIGH LIGHTEXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED) THROUGH MULTIPLEEXTRACTORS,” and U.S. Provisional Patent Application Ser. No.60/883,977, filed on Jan. 8, 2007, by Aurelien J. F. David, Claude C. A.Weisbuch and Steven P. DenBaars entitled “HIGH LIGHT EXTRACTIONEFFICIENCY LIGHT EMITTING DIODE (LED) THROUGH MULTIPLE EXTRACTORS,”;

U.S. Utility patent application Ser. No. 11/940,853, filed on Nov. 15,2007, by Claude C. A. Weisbuch, James S. Speck and Steven P. DenBaarsentitled “HIGH EFFICIENCY WHITE, SINGLE OR MULTI-COLOUR LIGHT EMITTINGDIODES (LEDS) BY INDEX MATCHING STRUCTURES,”, which application claimsthe benefit under 35 U.S.C Section 119(e) of U.S. Provisional PatentApplication Ser. No. 60/866,026, filed on Nov. 15, 2006, by Claude C. A.Weisbuch, James S. Speck and Steven P. DenBaars entitled “HIGHEFFICIENCY WHITE, SINGLE OR MULTI-COLOUR LED BY INDEX MATCHINGSTRUCTURES,”;

U.S. Utility patent application Ser. No. 11/940,866, filed on Nov. 15,2007, by Aurelien J. F. David, Claude C. A. Weisbuch, Steven P. DenBaarsand Stacia Keller, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHTEMITTING DIODE (LED) WITH EMITTERS WITHIN STRUCTURED MATERIALS,” nowU.S. Pat. No. 7,977,694 issued Jul. 12, 2011, which application claimsthe benefit under 35 U.S.C Section 119(e) of U.S. Provisional PatentApplication Ser. No. 60/866,015, filed on Nov. 15, 2006, by Aurelien J.F. David, Claude C. A. Weisbuch, Steven P. DenBaars and Stacia Keller,entitled “HIGH LIGHT EXTRACTION EFFICIENCY LED WITH EMITTERS WITHINSTRUCTURED MATERIALS,”;

U.S. Utility patent application Ser. No. 11/940,876, filed on Nov. 15,2007, by Evelyn L. Hu, Shuji Nakamura, Yong Seok Choi, Rajat Sharma andChiou-Fu Wang, entitled “ION BEAM TREATMENT FOR THE STRUCTURAL INTEGRITYOF AIR-GAP III-NITRIDE DEVICES PRODUCED BY PHOTOELECTROCHEMICAL (PEC)ETCHING,” which application claims the benefit under 35 U.S.C Section119(e) of U.S. Provisional Patent Application Ser. No. 60/866,027, filedon Nov. 15, 2006, by Evelyn L. Hu, Shuji Nakamura, Yong Seok Choi, RajatSharma and Chiou-Fu Wang, entitled “ION BEAM TREATMENT FOR THESTRUCTURAL INTEGRITY OF AIR-GAP III-NITRIDE DEVICES PRODUCED BYPHOTOELECTROCHEMICAL (PEC) ETCHING,”;

U.S. Utility patent application Ser. No. 11/940,885, filed on Nov. 15,2007, by Natalie N. Fellows, Steven P. DenBaars and Shuji Nakamura,entitled “TEXTURED PHOSPHOR CONVERSION LAYER LIGHT EMITTING DIODE,”which application claims the benefit under 35 U.S.C Section 119(e) ofU.S. Provisional Patent Application Ser. No. 60/866,024, filed on Nov.15, 2006, by Natalie N. Fellows, Steven P. DenBaars and Shuji Nakamura,entitled “TEXTURED PHOSPHOR CONVERSION LAYER LIGHT EMITTING DIODE,”;

U.S. Utility patent application Ser. No. 11/940,872, filed on Nov. 15,2007, by Steven P. DenBaars, Shuji Nakamura and Hisashi Masui, entitled“HIGH LIGHT EXTRACTION EFFICIENCY SPHERE LED,” which application claimsthe benefit under 35 U.S.C Section 119(e) of U.S. Provisional PatentApplication Ser. No. 60/866,025, filed on Nov. 15, 2006, by Steven P.DenBaars, Shuji Nakamura and Hisashi Masui, entitled “HIGH LIGHTEXTRACTION EFFICIENCY SPHERE LED,”;

U.S. Utility patent application Ser. No. 11/940,883, filed on Nov. 15,2007, by Shuji Nakamura and Steven P. DenBaars, entitled “STANDINGTRANSPARENT MIRRORLESS LIGHT EMITTING DIODE,” now U.S. Pat. No.7,687,813 issued Mar. 30, 2010, which application claims the benefitunder 35 U.S.C Section 119(e) of U.S. Provisional Patent ApplicationSer. No. 60/866,017, filed on Nov. 15, 2006, by Shuji Nakamura andSteven P. DenBaars, entitled “STANDING TRANSPARENT MIRROR-LESS (STML)LIGHT EMITTING DIODE,”;

U.S. Utility patent application Ser. No. 11/940,898, filed on Nov. 15,2007, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled“TRANSPARENT MIRRORLESS LIGHT EMITTING DIODE,” now U.S. Pat. No.7,781,789 issued Aug. 24, 2010, which application claims the benefitunder 35 U.S.C Section 119(e) of U.S. Provisional Patent ApplicationSer. No. 60/866,023, filed on Nov. 15, 2006, by Steven P. DenBaars,Shuji Nakamura and James S. Speck, entitled “TRANSPARENT MIRROR-LESS(TML) LIGHT EMITTING DIODE,”;

U.S. Utility patent application Ser. No. 11/954,163, filed on Dec. 11,2007, by Steven P. DenBaars and Shuji Nakamura, entitled “LEAD FRAME FORTRANSPARENT MIRRORLESS LIGHT EMITTING DIODE,”, which claims the benefitunder 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No.60/869,454, filed on Dec. 11, 2006, by Steven P. DenBaars and ShujiNakamura, entitled “LEAD FRAME FOR TM-LED,”;

U.S. Utility patent application Ser. No. 12/001,286, filed on Dec. 11,2007, by Mathew C. Schmidt, Kwang Choong Kim, Hitoshi Sato, Steven P.DenBaars, James S. Speck, and Shuji Nakamura, entitled “METALORGANICCHEMICAL VAPOR DEPOSITION (MOCVD) GROWTH OF HIGH PERFORMANCE NON-POLARIII-NITRIDE OPTICAL DEVICES,” now U.S. Pat. No. 7,842,527 issued Nov.30, 2010, which claims the benefit under 35 U.S.C. 119(e) of U.S.Provisional Patent Application Ser. No. 60/869,535, filed on Dec. 11,2006, by Mathew C. Schmidt, Kwang Choong Kim, Hitoshi Sato, Steven P.DenBaars, James S. Speck, and Shuji Nakamura, entitled “MOCVD GROWTH OFHIGH PERFORMANCE M-PLANE GAN OPTICAL DEVICES,”;

U.S. Utility patent application Ser. No. 12/001,227, filed on Dec. 11,2007, by Steven P. DenBaars, Mathew C. Schmidt, Kwang Choong Kim, JamesS. Speck, and Shuji Nakamura, entitled, “NON-POLAR AND SEMI-POLAREMITTING DEVICES,” which claims the benefit under 35 U.S.C. 119(e) ofU.S. Provisional Patent Application Ser. No. 60/869,540, filed on Dec.11, 2006, by Steven P. DenBaars, Mathew C. Schmidt, Kwang Choong Kim,James S. Speck, and Shuji Nakamura, entitled, “NON-POLAR (M-PLANE) ANDSEMI-POLAR EMITTING DEVICES,”; and

U.S. Utility patent application Ser. No. 11/954,172, filed on Dec. 11,2007, by Kwang Choong Kim, Mathew C. Schmidt, Feng Wu, Asako Hirai,Melvin B. McLaurin, Steven P. DenBaars, Shuji Nakamura, and James S.Speck, entitled, “CRYSTAL GROWTH OF M-PLANE AND SEMIPOLAR PLANES OF (AL,IN, GA, B)N ON VARIOUS SUBSTRATES,” which claims the benefit under 35U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No.60/869,701, filed on Dec. 12, 2006, by Kwang Choong Kim, Mathew C.Schmidt, Feng Wu, Asako Hirai, Melvin B. McLaurin, Steven P. DenBaars,Shuji Nakamura, and James S. Speck, entitled, “CRYSTAL GROWTH OF M-PLANEAND SEMIPOLAR PLANES OF (AL, IN, GA, B)N ON VARIOUS SUBSTRATES,”; all ofwhich applications are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to light extraction from light emittingdiodes (LEDs).

2. Description of the Related Art

(Note: This application references a number of different publications asindicated throughout the specification. In addition, a list of a numberof different publications can be found below in the section entitled“References.” Each of these publications is incorporated by referenceherein.)

In order to increase the light output power from the front side of alight emitting diode (LED), the emitted light is reflected by a mirrorplaced on the backside of the substrate or is reflected by a mirrorcoating on the lead frame, even if there are no mirrors on the backsideof the substrate, if the bonding material is transparent on the emissionwavelength. However, this reflected light is re-absorbed by the emittinglayer (active layer), because the photon energy is almost same as theband-gap energy of the light emitting species, such as AlInGaN multiplequantum wells (MQWs). The efficiency or output power of the LEDs isdecreased due to this re-absorption of the light by the emitting layer.See, for example, FIGS. 1, 2 and 3, which are described in more detailbelow. See also Jpn. J. Appl. Phys., 34, L797-99 (1995) and Jpn. J.Appl. Phys., 43, L180-82 (2004).

What is needed in the art are LED structures that more effectivelyextract light. The present invention satisfies that need.

SUMMARY OF THE INVENTION

The present invention describes a transparent light emitting diode.Generally, the present invention describes a light emitting devicecomprised of a plurality of III-nitride layers, including an activeregion that emits light, wherein all of the layers except for the activeregion are transparent for an emission wavelength of the light, suchthat the light is extracted effectively through all of the layers and inmultiple directions through the layers. Moreover, the surface of one ormore of the III-nitride layers may be roughened, textured, patterned orshaped to enhance light extraction.

In one embodiment, the III-nitride layers reside on a transparentsubstrate or sub-mount, wherein the III-nitride layers are wafer bondedwith the transparent substrate or sub-mount using a transparent glue, atransparent epoxy, or other transparent material, and light is extractedthrough the transparent substrate or sub-mount. The transparentsubstrate or sub-mount are electrically conductive, as is thetransparent glue, transparent epoxy, or other transparent material.

A lead frame supports the III-nitride layers (as well as the transparentsubstrate or sub-mount), which reside on a transparent plate in the leadframe. Thus, the light emitted from the III-nitride layers istransmitted through the transparent plate in the lead frame.

Moreover, the device may include one or more transparent conductinglayers that are positioned to electrically connect the III-nitridelayers, and one or more current spreading layers that are deposited onthe III-nitride layers, wherein the transparent conducting layers aredeposited on the current spreading layers. Mirrors or mirrored surfacesare eliminated from the device to minimize internal reflections in orderto minimize re-absorption of the light by the active region.

In another embodiment, the III-nitride layers are embedded in orcombined with a shaped optical element, and the light is extracted frommore than one surface of the III-nitride layers before entering theshaped optical element and subsequently being extracted. Specifically,at least a portion of the light entering the shaped optical element lieswithin a critical angle and is extracted. Moreover, one or more surfacesof the shaped optical element may be roughened, textured, patterned orshaped to enhance light extraction. Further, the shaped optical elementmay include a phosphor layer, which may be roughened, textured,patterned or shaped to enhance light extraction. The shaped opticalelement may be an inverted cone shape, wherein the III-nitride layersare positioned within the inverted cone shape such that the light isreflected by sidewalls of the inverted cone shape.

In yet another embodiment, an insulating layer covering the III-nitridelayers is partially removed, and a conductive layer is deposited withina hole or depression in the surface of the insulating layer to makeelectrical contact with the III-nitride layers.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers representcorresponding parts throughout:

FIGS. 1, 2 and 3 are cross-sectional schematic illustrations ofconventional LEDs.

FIGS. 4A and 4B are schematic and plan view illustrations, respectively,of an improved LED structure according to the preferred embodiment ofthe present invention.

FIGS. 5A and 5B are schematic and plan view illustrations, respectively,of an improved LED structure according to the preferred embodiment ofthe present invention.

FIG. 6 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIG. 7 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIGS. 8A and 8B are schematic and plan view illustrations, respectively,of an improved LED structure according to the preferred embodiment ofthe present invention.

FIG. 9 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIGS. 10A and 10B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIG. 11 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIGS. 12A and 12B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIG. 13 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIG. 14 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIGS. 15A and 15B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIG. 16 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIG. 17 is a schematic illustration of an improved LED structureaccording to the preferred embodiment of the present invention.

FIGS. 18A and 18B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIGS. 19A and 19B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIGS. 20A and 20B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIGS. 21A and 21B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

FIGS. 22A and 22B are schematic and plan view illustrations,respectively, of an improved LED structure according to the preferredembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description of the preferred embodiment, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown by way of illustration a specific embodiment in which theinvention may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

Overview

In the following description of the figures, the details of the LEDstructures are not shown. Only the emitting layer (usually AlInGaN MQW),p-type GaN layer, n-type GaN layer and sapphire substrate are shown. Ofcourse, there may be other layers in the LED structure, such as ap-AlGaN electron blocking layer, InGaN/GaN super lattices and others. Inthis invention, the most important aspects are the surfaces of the LEDstructure, because the light extraction efficiency is determined mainlyby the surface layer or condition of the epitaxial wafers. Consequently,only some aspects (the surface layers) of the LED are shown in all ofthe figures.

Conventional LED Structures

FIGS. 1, 2 and 3 are schematic illustrations of conventional LEDs.

In conventional LEDs, in order to increase the light output power fromthe front side of the LED, the emitting light is reflected by the mirroron the backside of the sapphire substrate or the mirror coating on thelead frame even if there is no mirrors on the backside of the sapphiresubstrate and if the bonding material is transparent on the emissionwavelength. This reflected light is re-absorbed by the emitting layer(active layer) because the photon energy is almost same as the band-gapenergy of the quantum well of AlInGaN multi-quantum well (MQW). Then,the efficiency or output power of the LEDs is decreased due to there-absorption by the emitting layer.

In FIG. 1, a conventional LED includes a sapphire substrate 100,emitting layer 102 (active layer), and semi-transparent or transparentelectrodes 104, such as ITO or ZnO. The LED is die-bonded on a leadframe 106 with a clear epoxy molding 108 without any mirror on the backside of the sapphire substrate 100. In this case, the coating materialon the lead frame 106, or the surface of the lead frame 106, becomes amirror 110. If there is a mirror 110 on the back side of the substrate100, the LED chip is die-bonded using an Ag paste. The active layer 102emits light 112 towards the substrate 100 and emits light 114 towardsthe electrodes 104. The emitting light 112 is reflected by the mirror110 towards the electrode 104, becoming reflected light 116 which istransmitted by the electrode 104 to escape the LED. The LED is wirebonded 118 to the lead frame 106.

In FIG. 2, the conventional LED is similar to that shown in FIG. 1,except that it is a flip-chip LED. The LED includes a sapphire substrate200 and emitting layer 202 (active layer), and a highly reflectivemirror 204. The LED is die-bonded 206 onto a lead frame 208 and embeddedin a clear epoxy molding 210. The active layer 202 emits light 212towards the substrate 200 and emits light 214 towards the highlyreflective mirror 204. The emitting light 214 is reflected by the mirror204 towards the substrate 200, becoming reflected light 216 which istransmitted by the substrate 200 to escape the LED.

In FIG. 3, the conventional LED includes a conducting sub-mount 300,high reflectivity mirror 302 (with Ag>94% reflectivity (R)), atransparent ITO layer 304, a p-GaN layer 306, an emitting or activelayer 308, and an n-GaN layer 310. The LED is shown without the epoxymolding, although similar molding may be used. The emitting layer 308emits LED emissions 312 towards the mirror 302 and emits LED emissions314 towards the n-GaN layer 310. The emission 312 of the emitting layer308 is reflected by the mirror 302, where the reflective light emissions316 are re-absorbed by the emitting layer 308. The efficiency of the LEDis decreased due to this re-absorption. The n-GaN layer may be roughened317 to enhance extraction 318 of LED emissions 314.

Improved LED Structures

The present invention describes a transparent LED. Generally, thepresent invention describes a light emitting device comprised of aplurality of III-nitride layers, including an active region that emitslight, wherein all of the layers except for the active region aretransparent for an emission wavelength of the light, such that the lightis extracted effectively through all of the layers and in multipledirections through the layers. The surface of one or more of theIII-nitride layers may be roughened, textured, patterned or shaped toenhance light extraction.

FIG. 4A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an emitting layer 400, an n-type GaNlayer 402, a p-type GaN layer 404, a first ITO layer 406, a second ITOlayer 408, and a glass layer 410. The n-type GaN layer 402 may havesurface 412 that is roughened, textured, patterned or shaped (e.g., acone shaped surface), and the glass layer 410 may have a surface 414that is roughened, textured, patterned or shaped (e.g., a cone shapedsurface). The LED is wire bonded 416 to a lead frame 418 via bondingpads 420, 422. FIG. 4B shows a top view of the lead frame 418.

In FIG. 4A, the LED structure is grown on a sapphire substrate, which isremoved using a laser de-bonding technique. Thereafter, the first ITOlayer 406 is deposited on the p-type GaN layer 404. The LED structure isthen attached to the glass layer 410, which is coated by the second ITOlayer 408, using an epoxy as a glue. The LED structure is then wirebonded 416 to the lead frame 418.

In FIG. 4A, there are no intentional mirrors at the front or back sidesof the LED. Instead, the lead frame 418 is designed to effectivelyextract light 424 from both sides of the LED, because the frame 418 doesnot obstruct the surfaces 412 and 414, i.e., the back side 426 of theLED as well as the front side 428 of the LED. FIG. 4B shows that theframe 418 supports the LED at the edges of the glass layer 410, leavingthe emitting surface of the glass layer 410 and LED unobstructed.

An ohmic contact may be placed below the bonding pad 420 on the n-GaNlayer 402, but is not shown in the figure for simplicity.

FIG. 5A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN multiple quantum well (MQW)layer as an emitting layer 500, an n-type GaN layer 502, a p-type GaNlayer 504, an ITO or ZnO layer 506, a transparent insulating layer 508,and transparent conductive glue 510 for bonding the ITO or ZnO layer 506to a transparent conductive substrate 512. The transparent conductivesubstrate 512 may have a surface 514 that is roughened, textured,patterned or shaped (e.g., a cone shaped surface), and the n-GaN layer504 may have a surface 516 that is roughened, textured, patterned orshaped (e.g., a cone shaped surface). Preferably, the layers 500, 502,504 and 506 have a combined thickness 518 of approximately 5 microns,and the substrate 512 and glue 510 have a combined thickness 520 ofapproximately 400 microns. Finally, ohmic electrode/bonding pads 522,524 are placed on the LED.

The LED structure may be grown on a sapphire substrate, which is removedusing a laser de-bonding technique. The ITO layer 506 is then depositedon the p-type GaN layer 504. Before deposition of the ITO layer 506, theinsulating layer 508, which may comprise SiO₂ or SiN, is deposited as acurrent spreading layer. Without the current spreading layer 508, theemission intensity of the LED becomes small due to non-uniform currentflows. The transparent conductive substrate 512, which may be ZnO,Ga₂O₃, or another material that is transparent at the desiredwavelengths, is wafer bonded or glued to the ITO layer 506 using thetransparent conductive glue 510. Then, an n-GaN ohmic electrode/bondingpad 522 and an p-GaN ohmic electrode/bonding pad 524 are formed on bothsides of the LED structure. Finally, the nitrogen-face (N-face) of then-type GaN layer 502 is roughened, textured, patterned or shaped 516 toenhance light extraction, for example, using a wet etching, such as KOHor HCL, to form a cone-shaped surface 516.

FIG. 5B is a plan view of the LED of FIG. 5A, and shows the LED placedon a transparent plate 526, which resides on a lead frame 528, both ofwhich work to remove heat from the LED. The p-side of the LED (i.e., theside with the substrate 512) is attached to the transparent plate 526.Wire bonding is performed between the bonding pad 524 of the n-type GaNlayer 502 and the lead frame 528.

There are no intentional mirrors at the front 530 or back sides 532 ofthe LED. Instead, the lead frame 528 is designed to effectively extractlight from both sides of the LED, i.e., the back side 532 of the LED aswell as the front side 530 of the LED.

Finally, an ohmic contact may be placed below the bonding pad 524 of then-GaN layer 502. However, this ohmic contact is not shown in the figurefor simplicity.

FIG. 6 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN MQW active layer 600, an n-GaNlayer 602, a p-GaN layer 604, an epoxy layer 606 (which is approximately400 microns thick 608), a bonding pad 610, an ohmic electrode/bondingpad 612, and an ITO or ZnO layer 614. The combined thickness 616 of then-GaN layer 602, active layer 600 and p-GaN layer 604 is approximately 5microns.

FIG. 7 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN MQW active layer 700, an n-GaNlayer 702, a p-GaN layer 704, an epoxy layer 706 (approximately 400microns thick 708), a narrow stripe Au connection 710, a bonding pad712, an ohmic electrode/bonding pad 714, and ITO or ZnO 716. Thethickness 718 of the n-GaN 702, active layer 700 and p-GaN layer 704 isapproximately 5 microns.

In both FIGS. 6 and 7, a thick epoxy layer 606, 706 is used, rather thanthe glass layer 410 shown in FIG. 4. To make electrical contact, theepoxy insulating layers 606, 706 are partially removed, and the ITOlayer 614, which is a transparent metal oxide, or a narrow stripe of Auor other metal layer 710, are deposited on the epoxy layers 606, 706, aswell as within a hole or depression 618, 720 in the surface of the epoxylayers 606, 706, to make electrical; contact with the p-GaN layer 604,704.

In addition, both FIGS. 6 and 7 show that roughened, textured, patternedor shaped surfaces 620, 722 are formed on the nitrogen face (N-face) ofthe n-type GaN layers 602, 702. These roughened, textured, patterned orshaped surfaces 620, 722 enhance light extraction.

Note that, if a GaN substrate is used instead of a sapphire substrate,laser de-bonding would not be required and, a result, the sub-mounts606, 706 would not be required. Moreover, if the LED structure iscreated on a GaN substrate, the ITO layer 614 would be deposited on thep-type GaN layer 604 and the backside of the GaN substrate, which is anN-face GaN, could be etched using a wet etching, such as KOH and HCL inorder to form surfaces 620, 722 that are roughened, textured, patternedor shaped on the n-type GaN layers 602, 702.

Note also that, if the surface of the ITO layer 614 is roughened,textured, patterned or shaped, light extraction is increased through theITO layer 614. Even without the ITO layer 614 on the p-type GaN layer604, the roughening, texturing, patterning or shaping of the surface ofthe p-type GaN layer 604 is effective to increase the light extractionthrough the p-type GaN layer 604.

Finally, an ohmic contact for the n-type GaN layer 612, and the ITO orZnO layer 614 may be used after the surface 620 roughening, texturing,patterning or shaping of the n-type GaN layer 602. The ITO or ZnO layer614 has a similar refractive index as GaN and, as a result, the lightreflection at the interface between the ITO, ZnO and GaN is minimized.

FIG. 8A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an emitting layer 800, an n-type GaNlayer 802, a p-type GaN layer 804, a first ITO layer 806, a second ITOlayer 808, and a glass layer 810. The n-type GaN layer 802 has a surface812 that is roughened, textured, patterned or shaped (e.g., a cone shapesurface), and the glass layer 810 has a surface 814 that is roughened,textured, patterned or shaped (e.g., a cone shape surface). The LED iswire bonded 816 to a lead frame or sub-mount 818 using the bonding pads820, 822.

The LED may be embedded with or contained in a molding or shaped opticalelement 824, such as a sphere made of epoxy or glass, forming, forexample, a lens. The shaped optical element 824 may include a phosphorlayer 826, which may be remote from the LED, that is roughened,textured, patterned or shaped, for example, on an outer surface of theshaped optical element 824. In this embodiment, the emitting layer 800emits light 828 towards the surfaces 812 and 814, where the light can beextracted 830.

In this embodiment, because the shaped optical element 824 is a sphere,the LED structure can be considered a small spot light source, becausethe direction of all of the light emitted from the LED is substantiallynormal to the interface between air and the sphere 824, and the lighttherefrom is effectively extracted to air through the interface betweenair and the sphere 824.

In addition, if the phosphor layer 826 is placed on or near the outersurface of the shaped optical element, the conversion efficiency, forexample, from blue light to white light, is increased due to reducedre-absorption of the light 828 resulting from reduced back scattering ofthe light 828 by the phosphor layer 826. Moreover, if the surface 834 ofthe phosphor layer 826 is roughened, textured, patterned or shaped,light extraction is again increased.

Finally, FIG. 8B is a top view of the device in FIG. 8A, illustratingthe lead frame 818.

FIG. 9 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN MQW emitting layer 900, ann-type GaN layer 902, a p-type GaN layer 904, an ITO layer 906 having asurface 908 that is roughened, textured, patterned or shaped, a bondingpad 910, an ohmic contact/bonding pad 912, a surface 914 of the n-typeGaN layer 902 that is roughened, textured, patterned or shaped, and anepoxy layer 916 that is deposited on the 908. The LED may be embeddedwith or contained in a molding or shaped optical element 918, such as asphere made of epoxy or glass, forming, for example, a lens. The shapedoptical element 918 may include a phosphor layer 920, which may beremote from the LED, that is roughened, textured, patterned or shaped,for example, on an outer surface of the shaped optical element 918.

In FIG. 9, the ITO or ZnO layer 906 is roughened, textured, patterned orshaped to improve light extraction through the ITO or ZnO layer 906. Inaddition, the epoxy 918 is sub-mounted. Otherwise, the structure of FIG.9 is the same as that shown in FIGS. 6-8.

FIG. 10A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN MQW emitting layer 1000, ann-type GaN layer 1002, a p-type GaN layer 1004, an ITO layer 1006, abonding pad 1008, an ohmic contact/bonding pad 1010, a surface 1012 ofthe ITO layer 1006 that is roughened, textured, patterned or shaped, asurface 1014 of the n-type GaN layer 1002 that is roughened, textured,patterned or shaped, and an epoxy layer 1016 that is deposited on thesurface 1012.

The LED may be embedded with or contained in a molding or shaped opticalelement 1018, such as a sphere made of epoxy or glass, forming, forexample, a lens. The shaped optical element 1018 may include a phosphorlayer 1020, which may be remote from the LED, that is roughened,textured, patterned or shaped, for example, on an outer surface of theshaped optical element 1018.

The LED may also include a current spreading layer 1022, which maycomprise SiN, SiO₂, or some other insulating material, for example, isdeposited before the ITO or ZnO layer 1006 to flow the current uniformlythrough the p-type GaN layer 1004.

Finally, the LED is wire bonded 1024 to a lead frame 1026. FIG. 10Bshows a top view of the lead frame 1026.

FIG. 11 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an InGaN MQW emitting layer 1100, ann-type GaN layer 1102, a p-type GaN layer 1104, an ITO layer 1106, abonding pad 1108, an ohmic contact/bonding pad 1110, a surface 1112 ofthe ITO layer 1106 that is roughened, textured, patterned or shaped, asurface 1114 of the p-type GaN layer 1102 that is roughened, textured,patterned or shaped, and an epoxy layer 1116 that is deposited on thesurface 1112.

The LED may be embedded with or contained in a molding or shaped opticalelement 1118, such as a sphere made of epoxy or glass, forming, forexample, a lens. The shaped optical element 1118 may include a phosphorlayer 1120, which may be remote from the LED, that is roughened,textured, patterned or shaped, for example, on an outer surface of theshaped optical element 1118.

The LED may also include a current spreading layer 1122, which maycomprise SiN, SiO₂, or some other insulating material, for example, thatis deposited before the ITO or ZnO layer 1106 to flow the currentuniformly through the p-type GaN layer 1104.

Finally, the LED is wire bonded 1124 to a lead frame 1126. FIG. 11Bshows a top view of the lead frame 1126.

In the embodiment of FIG. 11, a mirror 1128 is placed outside of theshaped optical element 1118, in order to obtain more light from a frontside 1130 of the device. The shape of the mirror is designed to preventreflected light from reaching the LED, in order to reduce re-absorptionof the light by the LED.

FIG. 12A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an emitting layer 1200, an n-type GaNlayer 1202, a p-type GaN layer 1204, an ITO or ZnO layer 1206, and asubstrate 1208, which may be a flat sapphire substrate or a patternedsapphire substrate (PSS). The LED is wire bonded 1210 to a lead frame1212, and embedded in or combined with moldings or shaped opticalelements 1214, 1216, such as inverted cone shapes made of epoxy orglass, forming, for example, lenses. In this embodiment, the shapedoptical elements 1214, 1216 are formed on opposite sides, e.g., thetop/front and bottom/back sides of the LED, wherein the emitting layer1200 emits light 1222 that is extracted from both the top/front andbottom/back sides of the LED.

The LED is electrically connected to the lead frame 1218 via bondingpads 1224, 1226. The bonding pad 1224 is deposited on the ITO or ZnOlayer 1206, and the ohmic contact/bonding pad 1226 is deposited on then-type GaN layer 1202 after the n-type GaN 1202 layer is exposed by aselective etch through the p-type GaN layer 1204.

As noted above, the LED may be combined with epoxy or glass and moldedas an inverted cone-shapes 1214, 1216 for both the front 1218 and backsides 1220, wherein the inverted cone molding shape 1214, 1216 providesenhanced light extraction. Specifically, most of the light entering theinverted cone shapes 1214, 1216 lies within a critical angle and isextracted. The light is reflected to a top or emitting surface of theinverted cone shape 1214 by the side walls of the inverted cone shape1214 for emission through the top surface of the inverted cone shape1214, and similarly, the light is reflected to a bottom or emittingsurface of the inverted cone shape 1216 by the side walls of theinverted cone shape 1216 for emission through the bottom surface of theinverted cone shape 1214.

Finally, note that a patterned sapphire substrate (PSS) 1208 improvesthe light extraction efficiency through the interface 1228 between then-GaN layer 1202 and the substrate 1208. In addition, the backside 1230of the sapphire substrate 1208 may be roughened, textured, patterned orshaped (e.g., a cone shaped surface) to increase the light extractionefficiency.

FIG. 12B shows a top view of the lead frame 1212.

FIG. 13 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an emitting layer 1300, an n-type GaNlayer 1302, a p-type GaN layer 1304, an ITO or ZnO layer 1306, and asubstrate 1308, which may be a flat sapphire substrate or a patternedsapphire substrate (PSS). The LED is wire bonded 1310 to a lead frame1312, and embedded in or combined with moldings or shaped opticalelements 1314, 1316, such as inverted cone shapes made of epoxy orglass, forming, for example, lenses. In this embodiment, the shapedoptical elements 1314, 1316 are formed on opposite sides, e.g., thetop/front and bottom/back sides of the LED, wherein the emitting layer1300 emits light 1322 that is extracted from both the top/front andbottom/back sides of the LED.

The LED is electrically connected to the lead frame 1318 via bondingpads 1324, 1326. The bonding pad 1324 is deposited on the ITO or ZnOlayer 1306, and the ohmic contact/bonding pad 1326 is deposited on then-type GaN layer 1302 after the n-type GaN 1302 layer is exposed by aselective etch through the p-type GaN layer 1304.

As noted above, the LED may be combined with epoxy or glass and moldedas an inverted cone-shapes 1314, 1316 for both the front 1318 and backsides 1320, wherein the inverted cone molding shape 1314, 1316 providesenhanced light extraction. Specifically, most of the light entering theinverted cone shapes 1314, 1316 lies within a critical angle and isextracted. The light is reflected to a top or emitting surface of theinverted cone shape 1314 by the side walls of the inverted cone shape1314 for emission through the top surface of the inverted cone shape1314, and similarly, the light is reflected to a bottom or emittingsurface of the inverted cone shape 1316 by the side walls of theinverted cone shape 1316 for emission through the bottom surface of theinverted cone shape 1314. Moreover, the top/front surface 1328 of theshaped optical elements 1314, and the bottom/back surface 1330 of theshaped optical element 1316 may be roughened, textured, patterned, orshaped to increase the light extraction through the elements 1314, 1316.

FIG. 14 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 1400 includes an emitting layer 1402 and asubstrate 1404 (as well as other layers), and the substrate 1404 is aflat or patterned sapphire substrate. The LED 1400 is wire bonded 1406to a lead frame 1408, and embedded in or combined with moldings orshaped optical elements 1410, 1412, such as inverted cone shapes made ofepoxy or glass, forming, for example, lenses. In this embodiment, theshaped optical elements 1410, 1412 are formed on opposite sides, e.g.,the top/front side 1414 and bottom/back side 1416 of the LED 1400,wherein the emitting layer 1402 emits light 1418 that is extracted fromboth the top/front side 1414 and bottom/back side 1416 of the LED 1400.

In FIG. 14, phosphor layers 1420 may be placed near the top/frontsurface 1422 of the shaped optical element 1410 and the bottom/backsurface 1424 of the shaped optical element 1412. Preferably, thephosphor layers 1420 should be positioned as far away as possible fromthe LED 1400. In this case, the conversion efficiency of the blue lightto white light is increased, due to reduced re-absorption of the emittedlight by the LED 1400 resulting from reduced back-scattering of thelight by the phosphor layers 1420 to the LED 1400. Moreover, thesurfaces 1426 of the phosphor layers 1420 may be roughened, textured,patterned or shaped to improve light extraction.

FIG. 15A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 1500 comprises an emitting layer 1502, an n-typeGaN layer 1504, a p-type GaN layer 1506, an ITO or ZnO layer 1508, and asubstrate 1510, which may be a flat sapphire substrate or a patternedsapphire substrate (PSS).

The LED 1500 is wire bonded 1512 to a lead frame 1514, wherein FIG. 15Bis a schematic illustration showing the top view of the lead frame 1514.

In this embodiment, the LED 1500 is embedded in or combined withmoldings or shaped optical elements 1516, 1518, such as inverted coneshapes made of epoxy or glass, forming, for example, lenses. The shapedoptical elements 1516, 1518 are formed on opposite sides, e.g., thetop/front side 1520 and bottom/back side 1522 of the LED 1500, whereinthe emitting layer 1502 emits light 1524 that is extracted from both thetop/front side 1520 and bottom/back side 1522 of the LED 1500.

A mirror 1526 may be placed inside the shaped optical element 1518 toincrease the light output to the front side 1528 of the LED 1500.Moreover, the shape of the mirror 1526 is designed to preventreflections of the light 1530 emitted from the LED 1500 from beingre-absorbed by the LED 1500, which would reduce the output power or theefficiency of the LED. Instead, the mirror 1526 guides the reflectedlight 1530 away from the LED 1500.

In addition, the mirror 1526 is only partially attached (or not attachedat all) to the LED 1500 or the substrate 1510. This differs fromconventional LEDs, where mirrors are attached to the entire surface ofthe LED, for example, as shown in FIGS. 1-3.

FIG. 16 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure comprises an emitting layer 1600, an n-type GaNlayer 1602, a p-type GaN layer 1604, an ITO or ZnO layer 1606, and asubstrate 1608, which may be a flat sapphire substrate or a patternedsapphire substrate (PSS). The LED is wire bonded 1610 to a lead frame1612.

In this embodiment, the LED is embedded in or combined with moldings orshaped optical elements 1614, 1616, such as inverted cone shapes made ofepoxy or glass, forming, for example, lenses. The shaped opticalelements 1614, 1616 are formed on opposite sides, e.g., the top/frontside 1618 and bottom/back side 1620 of the LED, wherein the emittinglayer 1602 emits light 1622 that is extracted from both the top/frontside 1618 and bottom/back side 1620 of the LED.

A mirror 1624 may be placed inside the shaped optical element 1616 toincrease the light output to the front side 1626 of the LED. Moreover,the shape of the mirror 1624 is designed to prevent reflections of thelight 1628 emitted from the LED from being re-absorbed by the LED, whichwould reduce the output power or the efficiency of the LED. Instead, themirror 1624 guides the reflected light 1628 away from the LED.

In addition, the mirror 1624 is only partially attached (or not attachedat all) to the LED or the substrate 1608. This differs from conventionalLEDs, where mirrors are attached to the entire surface of the LED, forexample, as shown in FIGS. 1-3.

Finally, the top/front surface 1630 of the shaped optical element 1614is roughened, textured, patterned or shaped to improve light extractionefficiency.

FIG. 17 is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 1700 includes an emitting layer 1702 and asubstrate 1704 (as well as other layers), and the substrate 1704 is aflat or patterned sapphire substrate. The LED 1700 is wire bonded 1706to a lead frame 1708, and embedded in or combined with moldings orshaped optical elements 1710, 1712, such as inverted cone shapes made ofepoxy or glass, forming, for example, lenses. In this embodiment, theshaped optical elements 1710, 1712 are formed on opposite sides, e.g.,the top/front side 1714 and bottom/back side 1716 of the LED 1700,wherein the emitting layer 1702 emits light 1718 that is extracted fromboth the top/front side 1714 and bottom/back side 1716 of the LED 1700.

In FIG. 17, a mirror 1720 may be placed inside the shaped opticalelement 1712 to increase the light output directed to the front side1720 of the LED 1700. Moreover, a phosphor layer 1722 may be placed nearthe top surface 1724 of the shaped optical element 1710. Preferably, thephosphor layer 1722 is positioned as far away as possible from the LED1700. In this case, the conversion efficiency of the blue light to whitelight is increased, due to reduced re-absorption of the light 1718emitted from the LED 1700 resulting from reduced back-scattering by thephosphor layer 1722. In addition, the surface 1726 of the phosphor layer1722 may be roughened, textured, patterned or shaped to improve lightextraction through the phosphor layer 1722.

FIG. 18A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 1800 includes an emitting layer 1802 and asubstrate 1804 (as well as other layers). The LED 1800 is wire bonded1806 to a lead frame 1808, wherein FIG. 18B is an illustration showingthe top view of the lead frame 1808.

In this embodiment, the LED 1800 is embedded in or combined with amolding or shaped optical element 1810, such as an inverted cone shapemade of epoxy or glass, forming, for example, a lens. Light 1812 emittedby the emitting layer 1802 is reflected by mirrors 1814 positionedwithin the shaped optical element 1810, towards the front side 1816 ofthe shaped optical element 1810, away from the back side 1818 of theshaped optical element 1810, wherein the reflected light 1820 is outputfrom the shaped optical element 1810.

FIG. 19A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 1900 includes an emitting layer 1902 and asubstrate 1904 (as well as other layers). The LED 1900 is wire bonded1906 to a lead frame 1908, wherein FIG. 19B is an illustration showingthe top view of the lead frame 1908.

In this embodiment, the LED 1900 is embedded in or combined with amolding or shaped optical element 1910, such as an inverted cone shapemade of epoxy or glass, forming, for example, a lens. Light 1912 emittedby the emitting layer 1902 is reflected by the sidewalls 1914 of theshaped optical element 1910, towards the front side 1916 of the shapedoptical element 1910, wherein the reflected light 1918 is output fromthe shaped optical element 1910, and away from the back side 1920 of theshaped optical element 1910.

Preferably, the LED 1900 is positioned within the shaped optical element1910 such that the light 1912 emitted by the LED is reflected bymirrored surfaces 1922 of the sidewalls 1914, wherein the mirroredsurfaces 1922 are deposited or attached to the sidewalls 1914. The angle1924 of the sidewalls 1914 relative to the base 1920 of the shapedoptical element 1910 is a critical angle that reflects the light 1912emitted from the LED 1900 to the front side 1916 of the shaped opticalelement 1910. For example, the refractive index of epoxy is n₂=1.5, therefractive index of the air is n₁=1, and, as a result, the criticalangle of the reflection is sin⁻¹ (1/1.5). Therefore, the angle 1924 ofthe sidewalls 1914 should be more than sin⁻¹ (1/1.5). This results inthe reflected light 1912 from the LED 1900 being effectively extractedfrom the top surface 1928 of the shaped optical element in the directionlabeled by 1926.

FIG. 20A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure includes an emitting layer 2000 and a substrate2002 (as well as other layers). The LED is wire bonded 2004 to a leadframe 2006, wherein FIG. 20B is a top view of the lead frame 2006.

In this embodiment, the LED is embedded in or combined with a molding orshaped optical element 2008, such as an inverted cone shape made ofepoxy or glass, forming, for example, a lens. Light 2010 emitted by theemitting layer 2002 is reflected by the sidewalls 2012 of the shapedoptical element 2008, towards the front side 2014 of the shaped opticalelement 2008, wherein the reflected light 2016 is output from the shapedoptical element 2008, and away from the back side 2018 of the shapedoptical element 2008.

Preferably, the LED is positioned within the shaped optical element 2008such that the light 2010 emitted by the LED is reflected by thesidewalls 2012. Moreover, the front or top surface 2020 of the shapedoptical element 2008 is roughened, textured, patterned or shaped toincrease light extraction.

The angle 2022 of the sidewalls 2012 relative to the base 2018 of theshaped optical element 2008 is a critical angle that reflects the 2010emitted from the LED to the front side 2014 of the shaped opticalelement 2008. For example, the refractive index of epoxy is n₂=1.5, therefractive index of the air is n₁=1, and, as a result, the criticalangle of the reflection is sin⁻¹ (1/1.5). Therefore, the angle 2022 ofthe sidewalls 2012 should be more than sin⁻¹ (1/1.5). This results inthe reflected light 2010 from the LED being effectively extracted fromthe front surface 2020 of the shaped optical element 2008.

FIG. 21A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 2100 includes an emitting layer 2102 and asubstrate 2104 (as well as other layers). The LED 2100 is wire bonded2106 to a lead frame 2108, wherein FIG. 21B shows a top view of the leadframe 2108.

In this embodiment, the LED 2100 is embedded in or combined with amolding or shaped optical element 2110, such as an inverted cone shapemade of epoxy or glass, forming, for example, a lens. Preferably, theLED 2100 is positioned within the shaped optical element 2110 such thatthe light 2112 emitted by the LED is reflected by the sidewalls 2114 ofthe shaped optical element 2110, towards the front side 2116 of theshaped optical element 2110, wherein the reflected light 2118 is outputfrom the shaped optical element 2110, and away from the back side 2120of the shaped optical element 2110.

A phosphor layer 2122 may be placed on or near the front or top surface2124 of the shaped optical element 2110. Preferably, the phosphor layer2122 is placed as far away as possible from the LED 2100. In thisexample, the conversion efficiency of blue light to white light isincreased due to reduced re-absorption of the light 2112 by the LED 2100resulting from reduced back-scattering by the phosphor layer 2122. Inaddition, the surface 2126 of the phosphor layer 2122 may be roughened,textured, patterned or shaped to increase light extraction.

FIG. 22A is a schematic illustrating a specific improved LED structureaccording the preferred embodiment of the present invention, wherein theimproved LED structure 2200 includes an emitting layer 2202 and asubstrate 2204 (as well as other layers). The LED 2200 is wire bonded2206 to a lead frame 2208, wherein FIG. 22B shows a top view of the leadframe 2208.

The LED 2200 is embedded in or combined with moldings or shaped opticalelements 2210, 2212, such as inverted cone shapes made of epoxy orglass, forming, for example, lenses. In this embodiment, the shapedoptical elements 2210, 2212 are formed on opposite sides, e.g., thetop/front side 2214 and bottom/back side 2216 of the LED 2200, whereinthe emitting layer 2200 emits light 2218 that is extracted from both thetop/front side 2214 and bottom/back side 2216 of the LED 2200.

The lead frame 2208 includes a transparent plate 2220, wherein the LED2200 is bonded to the transparent plate 2220 using a transparent/clearepoxy 2222 as a die-bonding material. The transparent plate 2220 may becomprised of glass, quartz, sapphire, diamond or other materialtransparent for the desired emission wavelength, wherein the transparentglass plate 2220 effectively extracts the light 2218 emitted from theLED 2200 to the shaped optical element 2212.

Advantages and Improvements

One advantage of the present invention is that all of the layers of theLED are transparent for the emission wavelength, except for the emittinglayer, such that the light is extracted effectively through all of thelayers.

Moreover, by avoiding the use of intentional mirrors with the LED,re-absorption of light by the LED is minimized, light extractionefficiency is increased, and light output power is increased.

The combination of a transparent electrode with roughened, textured,patterned or shaped surfaces, with the LED embedded within a shapedoptical element or lens, results in increased light extraction.

REFERENCES

The following references are incorporated by reference herein:

-   1. Appl. Phys. Lett., 56, 737-39 (1990).-   2. Appl. Phys. Lett., 64, 2839-41 (1994).-   3. Appl. Phys. Lett., 81, 3152-54 (2002).-   4. Jpn. J. Appl. Phys., 43, L1275-77 (2004).-   5. Jpn. J. Appl. Phys., 45, L1084-L1086 (2006).-   6. Jpn. J. Appl. Phys., 34, L797-99 (1995).-   7. Jpn. J. Appl. Phys., 43, L180-82 (2004).-   8. Fujii T., Gao Y., Sharma R., Hu E. L., DenBaars S. P., Nakamura    S., “Increase in the extraction efficiency of GaN-based    light-emitting diodes via surface roughening,” Applied Physics    Letters, vol. 84, no. 6, 9 Feb. 2004, pp. 855-7.

CONCLUSION

This concludes the description of the preferred embodiment of thepresent invention. The foregoing description of one or more embodimentsof the invention has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching.

What is claimed is:
 1. A light emitting device, comprising: a lead framehaving a transparent plate therein; and a light emitting diode (LED)chip, mounted on the lead frame and placed on or above the transparentplate in the lead frame, emitting light through at least front and backsides of the LED chip; wherein the transparent plate in the lead frameallows the light emitted from the LED chip to be extracted out of theLED chip from the front or back sides of the LED chip and through thetransparent plate in the lead frame.
 2. The device of claim 1, wherein aside of the LED chip adjacent the transparent plate is roughened,textured or patterned, to increase extraction of the light emitted fromthe LED chip through the transparent plate in the lead frame.
 3. Thedevice of claim 2, wherein the side of the LED chip adjacent thetransparent plate that is roughened, textured or patterned comprises asurface of a p-type layer of the LED chip.
 4. The device of claim 2,wherein the side of the LED chip adjacent the transparent plate that isroughened, textured or patterned comprises a surface of an n-type layerof the LED chip.
 5. The device of claim 1, wherein the LED chip includesa transparent substrate and the transparent substrate is adjacent thetransparent plate.
 6. The device of claim 5, wherein the transparentsubstrate is roughened, textured, or patterned, to increase extractionof the light emitted from the LED chip through the transparent plate inthe lead frame.
 7. The device of claim 5, wherein the transparentsubstrate is a patterned sapphire substrate (PSS) that increasesextraction of the light emitted from the LED chip through an interfacebetween the LED chip and patterned sapphire substrate.
 8. The device ofclaim 1, wherein the transparent plate is roughened, textured orpatterned, to increase extraction of the light emitted from the LED chipthrough the transparent plate in the lead frame.
 9. The device of claim1, wherein the LED chip is embedded with or contained in a molding orshaped optical element that is transparent to the light emitted from theLED chip, and a phosphor layer is formed within, near a surface of, oron top of, the molding or shaped optical element, for wavelengthconversion of the light emitted from the LED chip.
 10. The device ofclaim 9, wherein at least a portion of the phosphor layer is roughened,textured, or patterned, to minimize internal reflection of the lightwithin the phosphor layer.
 11. The device of claim 9, further comprisinga mirror, placed outside of the molding or shaped optical element, inorder to obtain more of the light emitted from at least one side of theLED chip, wherein the mirror's shape prevents reflected light fromreaching the LED chip, in order to reduce re-absorption of the light bythe LED chip.
 12. The device of claim 1, further comprising at least onetransparent contact layer deposited on a surface of the LED chip that isshaped, patterned, textured or roughened to increase extraction of thelight emitted from the LED chip.
 13. The device of claim 1, wherein theLED chip is comprised of a plurality of III-nitride layers, including anactive region that emits light, wherein all of the layers except for theactive region are transparent for an emission wavelength of the light,such that the light is extracted effectively through all of the layersand in multiple directions through the layers.
 14. A method forfabricating a light emitting device, comprising: providing a lead framehaving a transparent plate therein; and mounting a light emitting diode(LED) chip on the lead frame, wherein the LED is placed on or above thetransparent plate in the lead frame; wherein light is emitted through atleast front and back sides of the LED chip; and wherein the transparentplate in the lead frame allows the light emitted from the LED chip to beextracted out of the LED chip from the front or back sides of the LEDchip and through the transparent plate in the lead frame.
 15. The methodof claim 14, wherein a side of the LED chip adjacent the transparentplate is roughened, textured or patterned, to increase extraction of thelight emitted from the LED chip through the transparent plate in thelead frame.
 16. The method of claim 15, wherein the side of the LED chipadjacent the transparent plate that is roughened, textured or patternedcomprises a surface of a p-type layer of the LED chip.
 17. The method ofclaim 15, wherein the side of the LED chip adjacent the transparentplate that is roughened, textured or patterned comprises a surface of ann-type layer of the LED chip.
 18. The method of claim 14, wherein theLED chip includes a transparent substrate and the transparent substrateis adjacent the transparent plate.
 19. The method of claim 18, whereinthe transparent substrate is roughened, textured, or patterned, toincrease extraction of the light emitted from the LED chip through thetransparent plate in the lead frame.
 20. The method of claim 18, whereinthe transparent substrate is a patterned sapphire substrate (PSS) thatincreases extraction of the light emitted from the LED chip through aninterface between the LED chip and patterned sapphire substrate.
 21. Themethod of claim 14, wherein the transparent plate is roughened, texturedor patterned, to increase extraction of the light emitted from the LEDchip through the transparent plate in the lead frame.
 22. The method ofclaim 14, wherein the LED chip is embedded with or contained in amolding or shaped optical element that is transparent to the lightemitted from the LED chip, and a phosphor layer is formed within, near asurface of, or on top of, the molding or shaped optical element, forwavelength conversion of the light emitted from the LED chip.
 23. Themethod of claim 22, wherein at least a portion of the phosphor layer isroughened, textured, or patterned, to minimize internal reflection ofthe light within the phosphor layer.
 24. The method of claim 22, furthercomprising placing a mirror outside of the molding or shaped opticalelement, in order to obtain more of the light emitted from at least oneside of the LED chip, wherein the mirror's shape prevents reflectedlight from reaching the LED chip, in order to reduce re-absorption ofthe light by the LED chip.
 25. The method of claim 14, furthercomprising depositing at least one transparent contact layer on asurface of the LED chip that is shaped, patterned, textured or roughenedto increase extraction of the light emitted from the LED chip.
 26. Themethod of claim 14, wherein the LED chip is comprised of a plurality ofIII-nitride layers, including an active region that emits light, whereinall of the layers except for the active region are transparent for anemission wavelength of the light, such that the light is extractedeffectively through all of the layers and in multiple directions throughthe layers.